Equalizing device for printing-machines.



BBS

T AVAILABLE COPY P..E. PRESGHLIN. B UALIZING DEVICE FOR PRINTING MACHINES.

APPLICATION FILED FEB. 28, 1912.

Patented NOV.-12, 1912.

UNITED STATES PATENT ()FFICE.

PAUL ERNST PRESCHLIN, F SCHLADERN-ON-THE-SIEG, GIEERJVIIAITY.

EQUAL'IZING DEVICE FOR PRINTING-MACHINES.

Specification of Letters Patent.

Patented Nov. 12, 1912.

Application filed February 28, 1812. Serial No. 880,475.

necessity that all rolls running at equal angular speed are given the same diameter, otherwise the smallerrolls would feed too slowly and if arranged behind the larger rolls, would hold back the web, which thereby is bound to tear. If however the smaller rolls are arranged in front of the larger rolls, the latter would feed too fast and thus cause continuous trouble and interruptions in the working of the machine. The differences in diameter of the printing rolls is a frequent occurrence caused by depriving them of their etching or engraving.

Now if one would venture to change the number of revolutions or the angular speed of the rolls, to agree with the different diameter of the printing rolls, in such way,

. or more rotating rolls, which act on a common printing web or endless band and which make the same number of revolutions dur: ing .a unit of time, may be given different diameters. Ways and means have been devised to compensatefor the reduction in the diameter of the rolls deprived of their etching or engraving by giving the rolls their original diameter. However this is a task which is expensive. In making use of the present invention it is not necessary to bring the rolls back to their original diameter every time they are prepared for a new etching or engraving, but only when the diameter is so much reduced that an equalization of the feed by the subject matter of the present invention is no. longer possible.

According to the present invention a com-' pensation is produced whereby the counter roll of one of the printing rolls is now and then lifted off from the latter, so as-to release the web from the pressure and to"- allow a tension roller to act on the web intermediate of the two printing rolls so as to pull up the web to an amount corresponding to the difference in the diameter of the rolls, whereupon the said counter roll approaches its printing roll again and the tension roll returns to its original position.

In the accompanying drawing Figure 1 is a longitudinal section ofa portion'of a printing machine having the device embodying my invention attached thereto. Fig. 2 is a modification of a detail and Fig. 3 1s a plan of a web or printed newspaper.

The web a, b, c, d, e, f, g, h (endless paper fabric and the like) to be printed is taken from a reel H and led by aid of a number of guide rolls pastthe printing rolls B and A, which act together with the counter rolls E and A to print and feed the web. At both sides of the smaller printing roll B the web is led under movable tension rolls C and G which are movable longitudinally to the machine simultaneously for instance by aid of a common slide or of levers M and M which are connected by a link or rod N. i A spring K tends to move .the tension rollers from the position shown in dotted to that shown in full' lines, in which they are arrested by a set-screw D.

The counter roll E, which may be coated with rubber or may be made to bear against an endless rubber band, is journaled on levers 0 which are pivotally attached to a fixed part P of the machine-frame and said roll E is normally pressed by the roll F, which also counteracts its bending strains against the printing roll B, which is in positive driving connection with the printing roll A in such mannrr that both rotate at the same angular speed." The roll F, which is provided with a flattened 0r concave part: G, is also driven in such way as to make a complete revolution on each revolution of the printing roll During the time, in which the counter -roll E is rolling on the surface of the roll F, the printing carried on by theroll A as well. as by the roll B. it the same time the roll A feeds on the web to a greater extent than the smaller roll B, the tension roll C moving thereby from the position shown in full lines into that shown in dotted lines, thus allowing of a shortening of this part of the web. At the end of each revolution the concave part G- of the roll F comes opposite the counter roll E, which for a n1 onicnt extends into the cavity G in" the action of the spring L, thus releasing the web from the pressure, e):- orted between t e coin ter roll and the print ing roll. This release has the eii'ect of t e tension rollers C and l giving way to ac tension of the spring A wh ch retrrn, the tension rollers to the r originai pOFtiOIl shown in full lines, and tl.u-. pul up so much 01 the weln as the an n .z s t l more of the web than the roll P. "we equaliza.ion takes place for in: ta ice, when newspapers or similar sheets are printed at such moment, when the margin not to be printed comes in between the counter roll and the printing roll, that is to say the places shown in Fig, 3 in hatched lines.

The lifting of the counter roll E can be carried out in different ways. In the modification shown in Fig. 2 t e counter roll V of the printing roll T is jnurnaled on arms Q of bell crank levers Q, the other arm Q? of which being provided with an anti friction roller U, bearing against the rim of a disk S provided with a cam B. On every revolution of the printing roll T and of the disk S connected with it, the cam R raises the roller U, thereby oscillating the bell crank lever Q thus increasing the tension of the spring W and thereby allowing the counter roll to release the web.

By adjusting the screw D, which can be done during the working of the machine, the amount of the intermittent motion of the tension rollers G and C can be alteredv diameter than the printing roll B. In such case'thecounter roll A. would have to be lOlall'lilQ ranging the tension rollers. When however the counter roll of the roll B retains its lifting device, the tension rollers need only be movable in the other direction.

I claim:

1. In a printing machine having a plurality oi? printing rolls running at the same angular speed and having dil'l'erent diameters, a counter roll for each printing roll, one counter-roll adapted to be intermit teutly raised from its printing roll, a tension ltll in front of the counter roll adapted to be raised and a second tension roll behind the counter roll, both tension rolls being adapted to move in unison and to bear on the web to be printed, so as to change the feed of the web, when released by the counter roll being raised from its printing roll.

2. In a machine for printing upon a web of paper, the combination of a pair of printing rolls of different diameters arranged one behind the other and rotatable at the same angular speed, a cylinder to press the web on one of said rolls and adapt ed to temporarily release its pressure on said web, a. movabletension roll engaging the web between the two printing rolls adapted to be moved from its normal position by the tension on the web, caused by the unequal diameters of the printing rolls, and means to return the tension roll to its normal position automatically during said release of pressure.

3. In a machine for printing upon a Web of paper, the combination of a pair of printin g rolls of different diameters arranged one behind the other and rotatable at the same angular speed, a cylinder to press the web on one of said rolls means for temporarily liberating the web from the pressure ofthe printing roll and the pressure cylinder, a movable tension roll engagin the web between the printing rolls adapted to be moved from its normal position by the tension on the web, caused by the printing rolls of unequal diameter rotating at the same angular speed, and means to return the ten sion roll to its normal position automatically during the liberation of the web.

4. In a machine for printing upon a web of paper, thecombination of a pair of print ing rolls of different diameters arranged one behind the other and rotatable at the same angular speed, a cylinder to press the web on one of said rolls, unwmfo temporarily liberating the web fr m .c pressure of the printing roll and the ie-sure cylinier at regular intervals. a movable tension roll engaging the web lu l-ween the printing rolls adapted to'be moved from its normal position by the tension on the web, caused by the printing rolls of unequal diameter at the same angular speed, and

raised instead of E, by correspondingly ar- 1 means to return the tension roll to its noreration of the Web.

5. In a machine for printing upon a paper Web, the combination of a pair of printing 5 rolls of different diameters and rotatable at the same angular speed, and means adapted to equalize the difference in the feed of the i mal position automatically during the lib- Web due to said unequal diameters (if the printing rolls and the equal angular speed of rotation thereof. I

PAUL ERNST PRESOHLIN. Witnesses:

Lotus VANDORY, Bussin F. DUNLAP. 

